ON any client host 
     You will have to source the client's profile

     source ~<clientUserID>/sqllib/db2cshrc
     eg: source ~db2leduc/sqllib/db2cshrc

     Issue the following Command

      % db2level
     

     DB21085I  This instance or install (instance name, where applicable: "db2cli")
     uses "64" bits and DB2 code release "SQL10012" with level identifier 
     "0203010E".
     Informational tokens are "DB2 v10.1.0.2", "s121127", "IP23394", and Fix Pack
     "2".  Product is installed at "/cse/local/pkg/db2/V10.1".

Using client db2c64 (64 bit but version 9)

    DB21085I  Instance "db2c64" uses "64" bits and DB2 code release "SQL09017" with 
      level identifier "02080107".
     Informational tokens are "DB2 v9.1.0.7", "s090308", "MI00273", and Fix Pack  
     " 7".
     Product is installed at "/cse/local/pkg/db2/V9.1".

This will only work on the server

To list the path where DB2 database products are installed on your system and 
list the DB2 database product level, enter:

   db2ls   
   This lists the installation path , level, fixpak, special install number , 
   installation    date , installer UID
   
db2ls -q -p -b baseInstallDirectory
    where q is querying a product or feature 
          p specifies that the listing displays products      
          b specifies the installation directory of the product 

db2ls is installed in /usr/local/bin  as a symlink at installation time 
If the host server has to be rebuild with a new operating system
This link will have to be recreated 


gold ~]$ db2ls

Install Path     Level       Fix Pack   Install Date    
-----------------------------------------------------------------

/local/dbms/V9   9.7.0.6        6       Wed Aug 29 17:17:30 2012   
/local/dbms/V10  10.1.0.0       0       Fri Sep 14 09:21:48 2012  

This will only work on the server host

The db2val tool verifies the core function of a DB2 copy by validating 
installation files,instances, database creation, connections to that database,
and the state of partitioned database environments. This validation can be helpful
if you have manually deployed a DB2  copy on Linux and UNIX operating systems using
tar.gz files. The db2val command can quickly ensure that all the configuration has 
been correctly done and ensure that the DB2  copy is what you expect it to be. 
You can specify instances and databases or you can run  db2val against all of the instances. The db2val command can be found in the DB2-install-
path\bin and sqllib/bin directory


   eg:
    gold ~]$ db2val
           Installation file validation for the DB2 copy installed at
           /local/dbms/V10 was successful.

• db2icrt
• db2iupdt